1. Field of the Invention
This invention relates to a method of manufacturing a composition with a high ganglioside content easily and quickly. Because the composition with a high ganglioside content that is manufactured by the method of this invention contains ganglioside at a high percentage, it is useful as a material used for various foods and drinks, medicines, chemical products, etc.
2. Description of the Related Art
Ganglioside is a general tenn for sphingoglycolipid that contains sialic acid and it is known that various molecular species exist. In recent years, biochemical research on ganglioside has been conducted actively and its physiological functions such as cell differentiation, nerve function, malignant alteration, viral infection and cell information transmission have been made known. Further, ganglioside is known to be contained in relatively large quantities in animal cell membranes and brains, fat globule membranes and so on.
Conventionally, for methods of manufacturing a composition with a high ganglioside content, a method to obtain fat globule membranes from buttermilk (Japanese Patent Laid-open No. 60-72819) and a method using ion-exchange resin (Japanese Patent Laid-open No. 2-207090) are known. However, the former method has a problem in that it is very difficult to manufacture a composition with a high ganglioside content on an industrial scale and the latter method has a problem in that it is not suitable for volume processing because it uses ion-exchange resin. The inventors of the present invention previously proposed a method using ethanol as an easy method of manufacturing a composition with a high ganglioside content (Japanese Patent Laid-open No. 9-291094).This method is capable of volume manufacture of a composition with a high ganglioside content, but it requires many procedures including a process in which the use of a membrane device is required.
A method to extract ganglioside from animal tissue using ethanol and propanol (Japanese Patent Laid-open No. 10-218892) is also known, but this is a technique that can only be applied to non-dry animal tissue. Using this method, it is difficult to manufacture in volume a composition with a high ganglioside content and it has a drawback that the recovery rate of ganglioside is very low.
Further, a method of preparing a composition with a high ganglioside content using methanol at the laboratory level (Tohru Nakao and Yoshio Hirabayashi, Ganglioside Research Method I, p.32, Gakkai-Shuppan Center, 1995) is also known. However, using methanol is hazardous and this method is not suitable for volume manufacture. Moreover, it is difficult to use the composition with a high ganglioside content obtained in this way as a food material.
Consequently, because of the existing circumstances, a method of easily and quickly manufacturing in volume a composition with a high ganglioside content and which can be used as a food material as well, is called for.